JP2001039010A - Ink jet recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent offset of an image by preparing a binder resin for forming an ink receiving layer by incorporating three components of an emulsion resin, at least one type of a water soluble resin and a water soluble resin except a starch and cellulose derivative. SOLUTION: In the ink jet recoding medium obtained by coating a support with an ink receiving layer containing a pigment and a binder resin, as the binder resin for forming the layer, a resin containing three components of an emulsion resin (A), at least one type of water soluble resin (B) selected from a starch and cellulose derivative, and a water soluble resin (C) except the starch and the cellulose derivative is used. Thus, an increase in a thickness and offset of an image are suppressed, and recording quality levels of both surfaces when perfect printed are improved. In this case, it is preferred to blend 20 to 125 pts.wt. of the resin (B) and 20 to 600 pts.wt. of the resin (C) with 100 pts.wt. of the resin (A).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink-jet recording medium, and more particularly to an ink-jet recording medium suitable for a double-sided recording type because both the increase in thickness and the set-off of an image are suppressed and the recording quality on both sides is excellent. For media.

[0002]

2. Description of the Related Art Ink-jet recording systems for printing on a recording medium with an aqueous ink have been widely used in recent years because they have various features such as high-speed, low noise, easy colorization, and clear images. Is increasing. As a recording medium that effectively reflects the features of this ink jet recording system, it has the property of sharpening the image while sufficiently absorbing the water-based ink on the surface of a support such as paper made mainly of pulp. Ink-jet recording paper having an ink receiving layer laminated thereon. In general, the ink receiving layer uses a pigment represented by silica as an ink receiving agent, and disperses the pigment in a binder resin such as carboxyl group-modified PVA (polyvinyl alcohol). It is laminated by coating. On the ink receiving layer, a gloss layer is laminated as necessary to make the surface of the recording paper glossy. As such ink jet recording papers, those having an ink receiving layer laminated on one side of a support and those laminated on both sides, that is, those for single side recording and both side recording are commercially available.

[0003]

By the way, a general ink jet printer has been supplied at a lower cost in recent years as an ink jet recording system, and on-demand printing (for example, album use or the like) has been carried out as vivid colors became familiar. (For pamphlets). When an image recorded on both sides is required for such an application, to apply an ink jet recording sheet for single-sided recording, the back sides of the two sheets are stuck together or the two sheets are back-to-back and clear. The method of binding to a file was adopted. However, such a method is complicated, and in addition, there is a problem that a wrinkle is generated at the time of bonding or a printed image is deteriorated due to an influence of a glue used for bonding at the time of storage. Is more preferred.

[0004] However, the conventional ink jet recording paper for double-sided recording has a thicker support in order to suppress set-off of an image, and as a result, the overall thickness is larger than that of ordinary recording paper. Further, particularly when recording an image having a large amount of ink such as a full-color image, a phenomenon such as cockling in which the surface becomes wrinkled due to excessive moisture may occur. This cockling is less likely to occur if the ink absorptivity is reduced by increasing the air permeability of the paper, but it is essential that the ink absorptivity be at least a certain level. Therefore, in order to ensure the ink absorbency, it has been considered to increase the thickness of the ink receiving layer or increase the water absorption of the ink receiving layer itself. However, when the ink receiving layer is thickened, the drying property is deteriorated, and a problem occurs in that an image that is not completely dried is touched to cause image contamination. In order to increase the water absorption of the ink receiving layer itself, a large amount of a water-soluble resin may be contained in the binder resin. However, in this case, the water resistance deteriorates. Therefore, an attempt was made to increase the ink absorbency by increasing the proportion of the pigment. In this case, however, the amount of the binder resin was suppressed, so that the strength of the ink receiving layer was reduced and the ink receiving layer became brittle. There was a problem that the image was destroyed during transportation.

As described above, the conventional ink jet recording paper for double-sided recording has a problem that it becomes thick to suppress set-off of an image, and it is difficult to achieve both ink absorbency and prevention of cockling. The present invention has been made in view of such circumstances, is capable of double-sided recording,
Not only is it excellent in image recording quality, such as its print density, image clarity, and image storability (light resistance, water resistance, moisture resistance, etc.), it also suppresses both increase in thickness and image set-off, and It is an object of the present invention to provide an ink jet recording medium that can achieve both ink absorption and prevention of cockling.

[0006]

The present inventors have made various studies on an ink jet recording medium comprising a support and an ink receiving layer containing a pigment and a binder resin. Emulsion resin (A) and at least one water-soluble resin selected from starch and cellulose derivatives as a binder resin constituting the receiving layer
(B) and a water-soluble resin other than starch and a cellulose derivative
It has been found that the use of the composition containing the three components (C) achieves the above object. The present invention has been made based on such findings, at least on one side of the support, in an ink jet recording medium coated with an ink receiving layer containing a pigment and a binder resin,
The binder resin contains three components: an emulsion resin (A), at least one water-soluble resin (B) selected from starch and a cellulose derivative, and a water-soluble resin (C) other than starch and a cellulose derivative. Features.
Further, in the present invention, a configuration in which a glossiness adjusting layer is laminated on the outermost surface of the ink receiving layer is a preferable embodiment in which added value is enhanced. The ink receiving layer and the gloss adjusting layer are laminated at least one layer at a time, but either one or more layers may be laminated, or two or three layers may be laminated.

The ink jet recording medium of the present invention has a structure in which the ink receiving layer is laminated on at least one surface of a support. When the ink receiving layer is laminated on only one surface, it is used as a single side recording medium. Can be In the present invention, a support in which an ink receiving layer is laminated on both surfaces of a support is also included. In this case, the support is used as a double-sided recording medium.
Further, the ink receiving layer according to the present invention may be laminated on one surface (front surface) of the support, and a conventional ink receiving layer containing polyvinyl alcohol as a main component may be laminated on the back surface to be used as a double-sided recording medium. In this case, first, an image is recorded on the surface on which the ink receiving layer according to the present invention is laminated, and then the image is recorded on the back surface. By prioritizing the recording surfaces in this way, the effects of the present invention can be fully utilized,
Image recording quality on both sides is maintained. Hereinafter, the constituent materials of the ink jet recording medium of the present invention will be described in detail.

(1) Support The support on which the ink receiving layer is coated includes LBKP,
Chemical pulp such as NBKP, GP, PGW, RMP, TM
Mechanical pulp such as P, CTMP, CMP, CGP, DIP
Wood pulp such as waste paper pulp, etc., or synthetic fiber pulp such as polyethylene fiber as a main component, and is used for ordinary papermaking such as pigments and sizing agents, fixing agents, retention improvers, paper strength enhancers, etc. One or more kinds of various additives are mixed as necessary, and base paper manufactured by a papermaking machine such as a fourdrinier paper machine, a circular net paper machine, or a twin wire paper machine is used.
Furthermore, paper obtained by subjecting the base paper to a size press or an anchor coat layer using starch, PVA, casein, gelatin, etc.,
Art paper, coat paper, cast coat paper, etc., which has been converted into baryta paper as used for photographic printing paper can be used.

Before the ink-receiving layer is coated on such a support, a machine calender, a TG, or the like is used for the purpose of improving smoothness and coating properties of the ink-receiving layer or finishing the photographic paper. The support can be further processed by a calendar device such as a calender or a soft calender.

In addition, as an approach from a laminate material on a support, a material which is made porous from the beginning so that the air permeability does not increase excessively, or a material which is laminated with an extremely thin film and made porous by heating or the like. It is also possible to use synthetic resins such as polyolefin, polyethylene, polypropylene, polyester, nylon, rayon, polyurethane and the like, and film materials made of these resins.

Next, preferable physical properties of the support will be described. The air permeability of the support needs to be at a level at which the air permeability of the entire inkjet recording medium is kept within a certain level even when the glossiness adjusting layer is applied. The air permeability is preferably from 10 to 1000 seconds, more preferably from 10 to 400 seconds, according to the Oken-type air permeability test method specified in “J. TAPPI Paper Pulp Test Method No. 5”. Second, and more preferably 10 to 100 seconds. An ink jet recording medium using a support having a gas permeability of more than 1000 seconds has a problem that the image recording quality is lowered, such as a decrease in ink absorbency, because the total gas permeability does not become lower than this. It is not preferable because it may become possible. Also, when a glossiness adjusting layer is laminated, the strength of the same layer is reduced, which may cause peeling or destruction or a decrease in ink absorbency, which may cause a deterioration in image recording quality. Retention is necessary.

The smoothness of the coated surface of the support is preferably as high as possible by a method that does not impair the rigidity of the support, in order to maximize the design of the ink jet recording medium. Specific numerical values of smoothness include
The smoothness according to the Oken-type smoothness test method defined in “J. TAPPI Paper Pulp Test Method No. 5” is preferably 100 seconds or more, more preferably 500 seconds or more, and still more preferably 1500 seconds or more. .

Regarding the stiffness of the support, if the support is too soft or too stiff, a problem may occur in the paper feeding process to the printer. Therefore, the specific stiffness is described in “J. TAPPI Paper Pulp Test Method No. 40”.
20 ° C, 65 according to the Gurley stiffness test method specified in
% RH is preferably in the range of 400 to 3600 mN in the vertical direction and 200 to 1800 mN in the horizontal direction, and is preferably in the range of 800 to 2500 mN in the vertical direction and 400 to 1000 mN in the horizontal direction. Is most preferred.

(2) Ink-Receiving Layer Pigment As the pigment contained in the ink-receiving layer of the present invention, one or more commonly known pigments that are insoluble or hardly soluble in water are used. For example, light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate,
Satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudo-boehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrohaloisite, magnesium carbonate, magnesium hydroxide, etc. Examples include white inorganic pigments, styrene-based plastic pigments, acrylic-based plastic pigments, polyethylene, microcapsules, organic pigments such as urea resins, and melamine resins.

The main component of the ink receiving layer is usually composed of a white pigment. As the white pigment, a porous inorganic pigment is preferable from the viewpoint of excellent drying properties and absorptivity of the inkjet ink, and examples thereof include porous synthetic amorphous silica, porous magnesium carbonate, and porous alumina. . Further, those satisfying both print quality and storage stability (room storage stability and light resistance to direct sunlight) are preferable,
For this purpose, sedimentation type and gel type porous amorphous silica or porous alumina having a specific surface area of about 200 to 600 g / m ² are preferable.

Binder Resin The most important feature of the present invention resides in that the following three components are used in combination at an appropriate mixing ratio as a binder resin contained in the ink receiving layer. (A) Emulsion resin As the emulsion resin, maleic anhydride resin, styrene-butadiene copolymer, conjugated diene copolymer emulsion such as methyl methacrylate-butadiene copolymer, a polymer of acrylic acid ester and methacrylic acid ester or An acrylic polymer emulsion such as a copolymer, a vinyl polymer emulsion such as an ethylene-vinyl acetate copolymer, or a functional group-modified polymer emulsion using a functional group-containing monomer such as a carboxyl group of these various polymers, Examples include copolymer resin emulsions such as melamine resin, urea resin, polymethyl methacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, and alkyd resin. Among these resins, an ethylene-vinyl acetate copolymer resin emulsion and a polyurethane resin emulsion are particularly preferable because they are particularly effective in improving image storability (light fastness, water fastness, and moisture fastness). (B) at least selected from starch and cellulose derivatives
One type of water-soluble resin is a modified starch such as oxidized starch, etherified starch, or cationized starch, carboxymethyl cellulose,
And cellulose derivatives such as hydroxyethyl cellulose. (C) Water-soluble resin other than starch and cellulose derivative As the resin, completely saponified or partially saponified PV
A, resins that are said to have good adhesive properties, such as carboxylic acid-modified PVA, silyl-modified PVA, acetoacetyl group-modified PVA, and polyvinyl acetal resin. Among them, partially saponified PVA and carboxylic acid-modified PVA are particularly preferable because of their excellent adhesiveness and image storability.

The mixing ratio of the pigment and the binder resin to be contained in the ink receiving layer is selected in such a range that the balance of the image recording quality such as the strength of the ink receiving layer, the strength of the gloss adjusting layer and the ink absorbency is maintained. . Specifically, pigment: binder resin = 3: 7 to 1: 1, emulsion resin (A):
Water-soluble resin (total amount of resin (B) and resin (C)) = 55: 4
5-19: 1 is preferred, and pigment: binder resin = 4:
6 to 1: 1, emulsion resin (A): water-soluble resin (total amount of resin (B) and resin (C)) = 3: 1 to 3: 2 is more preferable. If the amount of the pigment is too large, the ink receiving layer may be damaged during production due to insufficient adhesive strength of the binder resin, or the glossiness adjusting layer may be broken when a glossiness adjusting layer is laminated as necessary, thereby increasing productivity. It causes a decline. Conversely, if the amount of the binder resin is too large, the air permeability increases, which causes a decrease in image recording quality such as ink absorbency.

The above resin constituting the binder resin
The mixing ratio of (A), (B) and (C) is such that the water-soluble resin (B): 20 to 125 parts by weight and the water-soluble resin (C): 20 per 100 parts by weight of the emulsion resin (A). Preferably, it is blended in a proportion of up to 600 parts by weight. Further, the emulsion resin (A): 5.
0 to 28.0% by weight, water-soluble resin (B): 3.0 to 15.
0% by weight, water-soluble resin (C): 5.0 to 30.0% is preferred. If any one of these three components is lacking, the film-forming property of the ink receiving layer is improved, the air permeability is increased, and the image recording quality such as ink absorbency is reduced.

The air permeability of the ink receiving layer needs to be at a level at which the air permeability of the entire ink jet recording medium is kept within a certain level even when the gloss adjusting layer is applied. The air permeability is preferably from 10 to 300 seconds, more preferably from 10 to 200 seconds, according to the Oken-type air permeability test method specified in “J. TAPPI Paper and Pulp Test Method No. 5”. Second, and more preferably 10 to 150 seconds. If the air permeability of the ink receiving layer exceeds 300 seconds, it is not preferable because it may cause a decrease in image recording quality such as a decrease in ink absorbency. Also, when a glossiness adjusting layer is laminated, the strength of the same layer is reduced, which may cause peeling or destruction or a decrease in ink absorbency, which may cause a deterioration in image recording quality. Retention is necessary.

Other additives In the ink receiving layer, other additives such as a lightfastness improving agent, a dye / pigment fixing agent, a pigment dispersant, a thickener, a flow improver, an antifoaming agent and a foam inhibitor Agent, release agent, foaming agent, penetrant,
Coloring dyes, coloring pigments, optical brighteners, preservatives, water resistance agents,
A hardener and the like can be appropriately compounded as needed.

Here, an additive which has an effect of preventing light fading of an image by being added to the ink receiving layer is defined as the above-mentioned chemical for improving light resistance. Examples of the agent for improving light resistance include divalent or higher valent water-soluble metal salts, ultraviolet absorbers, antioxidants and the like. As the dye fixing agent, a cationic dye fixing agent is suitably used. Examples of the cationic dye fixing agent include polyamine resin-based materials and quaternary ammonium salt resin-based materials. A synergistic effect is considered between the lightfastness improving agent and the cationic dye fixing agent. Therefore, in order to further improve image recording quality, the ink receiving layer is preferably provided with a lightfastness improving agent: a cationic dye fixing agent, preferably in a ratio of 4: 1-1: 1, more preferably in a ratio of 3: 2-1: 3. And a pigment + binder resin: another additive, preferably 1
The solid content ratio is preferably 9: 1 to 4: 1, more preferably 9: 1 to 4: 1.

Further, the above-mentioned ultraviolet absorber and antioxidant are liquids obtained by esterifying a polycarboxylic acid and a functional part (ultraviolet absorbing part, antioxidant functional part) more than a powder of a type kneaded with a polyolefin resin. A type and a dispersion type in which a surfactant is dispersed together with the surfactant are preferable.

(3) Glossiness Adjusting Layer In the present invention, a configuration in which a glossiness adjusting layer is laminated on the outermost surface of the ink receiving layer is a preferred embodiment in which added value is enhanced. For example, when high glossiness is required, the glossiness adjustment layer preferably has a glossiness of 10 or more according to a 60-degree specular glossiness test method. The glossiness adjusting layer is, for example, a mixed solution of a pigment and a binder resin used for the ink receiving layer as a coating solution (a glossy adjusting layer precursor coating solution), and is applied to the surface of the ink receiving layer. It is laminated by doing. As the binder resin, a polyvinyl alcohol-based resin or a water-soluble acrylic resin is preferable, and as the pigment, colloidal silica or colloidal alumina is preferable. The glossiness can be set to medium gloss or slight gloss depending on the type of binder resin and the mixing ratio of the pigment.
Further, when the ink receiving layer is laminated on both sides of the support, the glossiness can be made different between the front and back sides.

The mixing ratio of the pigment and the binder resin in the glossiness adjusting layer is preferably such that the binder resin is contained in the pigment in an amount of 5 to 50% by weight, more preferably 5 to 30% by weight, from the viewpoint of sufficiently maintaining the gloss. Is more preferable.
The basis weight at which the glossiness adjusting layer exhibits good glossiness without impairing the function of the ink receiving layer is 3 to 25 g.
/ M ² , preferably 5 to 15 g / m ² .

The ink receiving layer of the ink jet recording medium of the present invention is composed mainly of the above-mentioned pigment and binder resin, and if necessary, other additives are added to form a coating liquid. And laminated. From the viewpoint of satisfying various conditions such as sufficient image recording quality and adhesion to a support and avoidance of production problems such as powder dropping during cutting, the solid content ratio of these materials is preferably a pigment. : 40 to 60% by weight, binder resin: 20 to 40% by weight, other additives: 1 to 4
It is preferred to be blended on the basis of 0%.

Next, a method of laminating an ink receiving layer and a glossiness adjusting layer on both sides of the support will be described. Prepare the above materials constituting the ink receiving layer at an appropriate mixing ratio,
These are dissolved or dispersed in a suitable solvent such as water or alcohol to prepare a coating liquid for an ink receiving layer. This coating liquid is applied on a support by using a coating machine such as a blade coater, a roll coater, an air knife coater, a bar coater, a rod blade coater, and a size press on or off as appropriate. The coating amount of the coating liquid, for example, preferably 5 to 30 g / ^{m 2} in one layer type, more preferably if 5 to 20 g / ^{m 2.} When a first ink receiving layer is laminated on a support and a second ink receiving layer is laminated thereon to form a two-layer type, the coating amount of the first ink receiving layer is 5 to 3 times.
Preferably ^{0g / m 2, 5~20g / m} 2 is more preferable. The coating amount of the second ink receiving layer is 5 to 15 g / m
² is preferable, and 5 to 10 g / m ² is more preferable. If the amount is less than the above range, sufficient ink absorbency and fixability may not be obtained. On the other hand, if the amount is too large, problems such as powder dropout may occur, leading to a decrease in productivity and an increase in cost. In particular, when the coating amount of the second ink receiving layer exceeds 15 g / m ² , it becomes difficult for the ink to pass through the second ink receiving layer, and bleeding may occur to deteriorate image clarity. . As described above, it is preferable to control the amount of the ink receiving layer coating liquid applied according to the number of the ink receiving layers to be laminated. Further, after application, finishing may be performed using a calendar such as a machine calendar, a TG calendar, a super calendar, and a soft calendar.

The overall air permeability at the stage of applying the ink receiving layer coating liquid on the support and coating the ink receiving layer (the preceding stage when the glossiness adjusting layer is laminated) is as follows: Since the air permeability of the ink receiving layer is maintained at 10 to 300 seconds, the air permeability of the support substantially applies. That is, the air permeability of the Oken-type air permeability test method specified in “J. TAPPI paper pulp test method No. 5” is preferably 10 to 1000 seconds, more preferably 10 to 1000 seconds. -400 seconds, more preferably 10-100 seconds. When the air permeability exceeds 1000 seconds, the air permeability of the final product does not become lower than this, so that it may cause a decrease in image recording quality such as a decrease in ink absorbability, and is therefore preferable. Absent. In addition, even when the glossiness adjusting layer is laminated, the strength of the layer is reduced to cause peeling or destruction, or the ink absorbency of the final product is reduced, which causes deterioration in image recording quality. Therefore, it is necessary to maintain the above air permeability.

Next, as a method of laminating the glossiness adjusting layer on the ink receiving layer, for example, a generally known mirror surface drum casting method can be mentioned. However, in manufacturing the ink jet recording medium of the present invention, a gloss adjusting layer precursor coating liquid is applied on the ink receiving layer laminated on the support, and a coating liquid layer is laminated. On the liquid layer, a film (for example, a polyolefin resin film, a tetrafluoroethylene resin film, a releasable siliconized resin film, etc.) having a smooth surface and selected according to the glossiness adjustment layer to be coated is laminated. A method of laminating the films by bringing them into close contact and drying the coating liquid layer and then peeling off the film is more preferable.

The lamination of the glossiness adjusting layer on the ink receiving layer can be performed simultaneously with the ink receiving layer coating process and on-machine without causing the coating condition of the glossiness adjusting layer to be deteriorated. No accompanying deterioration in image recording quality such as ink absorbency is observed. Further, if the glossiness adjusting layer is laminated off-machine, the air permeability of the entire medium can be easily adjusted, and the image recording quality can be more precisely controlled.

[0030]

EXAMPLES Next, examples and comparative examples based on the present invention will be shown to further clarify the effects of the present invention. In each of the examples and the comparative examples, the support had a basis weight of 160 g / m ² ,
A high-quality paper having an air permeability of 50 seconds was prepared, and the following materials were dissolved or dispersed in water to prepare a coating liquid for an ink receiving layer and a coating liquid for a glossiness adjusting layer. These coating liquids were sequentially applied to both surfaces. The ink receiving layer and the glossiness adjusting layer were respectively applied and dried to form an inkjet recording medium having a surface glossiness of 40. The mixing ratio was the ratio of the weight of the dry solid content, and the coating amount was 10.0 g / m ² for both the ink receiving layer and the glossiness adjusting layer unless otherwise specified. Also,
The three components listed as the binder resin include (A) an emulsion resin, (B) a water-soluble resin: at least one water-soluble resin selected from starch and a cellulose derivative, and (C) a water-soluble resin: other than starch and a cellulose derivative. Water-soluble resin.

[Material of the ink receiving layer] <Example 1> Binder resin (A) Emulsion resin Ethylene-vinyl acetate emulsion Emulsion made by Kuraray: Panflex OM-5500 10.0% by weight (B) Water-soluble resin Cation Chemically modified starch Daiwa Chemical Co., Ltd .: Soldine CP-13D 6.0% by weight (C) Water-soluble resin partially saponified PVA Kuraray Co., Ltd .: Kuraray Poval PVA420 24.0% by weight ・ White pigment silica gel Mizusawa Chemical Co., Ltd .: Mizukasil P- 78D 40.0% by weight ・ Cationic dye fixing agent Polyamine-based dye fixing agent Sumitomo Chemical Co., Ltd .: Sumirezu Resin 784S 10.0% by weight ・ Light fastness improving agent Water-soluble metal salt with a valency of 2 or more, manufactured by Tomita Pharmaceutical Co., Ltd. : 10.0% by weight of magnesium chloride S

Example 2 Binder resin (A) Emulsion resin Ethylene-vinyl acetate emulsion Emulsion manufactured by Kuraray Co., Ltd .: Panflex OM-5500 10.0% by weight (B) Water-soluble resin Oxidized starch Oji Cornstarch Co., Ltd .: Ace A 6.0% by weight (C) Water-soluble resin partially saponified PVA Kuraray Co., Ltd .: Kuraray Poval PVA420 24.0% by weight ・ White pigment silica gel Mizusawa Chemical Co., Ltd .: Mizukasil P-78D 40.0% by weight ・ Cationic dye Fixing agent Polyamine-based dye fixing agent Sumitomo Chemical Co., Ltd .: Sumirezu Resin 784S 10.0% by weight-Lightfastness improving agent Divalent or higher valent water-soluble metal salt Tomita Pharmaceutical Co., Ltd .: Magnesium chloride S 10.0% by weight

Example 3 Binder Resin (A) Emulsion Resin Ethylene-Vinyl Acetate Emulsion Manufactured by Kuraray Co., Ltd .: Panflex OM-5500 10.0% by weight (B) Water-soluble resin Carboxymethylcellulose Manufactured by Daiichi Kogyo Seiyaku : Cellogen 5A 6.0% by weight (C) Water-soluble resin Partially saponified PVA Kuraray Co., Ltd .: Kuraray Poval PVA420 24.0% by weight ・ White pigment silica gel Mizusawa Chemical Co., Ltd .: Mizukasil P-78D 40.0% by weight ・ Cation Soluble dye fixing agent Polyamine dye fixing agent Sumitomo Chemical Co., Ltd .: Sumireze Resin 784S 10.0% by weight-Lightfastness improving agent Divalent or higher valent water-soluble metal salt Tomita Pharmaceutical Co., Ltd .: Magnesium chloride S 10.0% %

Example 4 Binder resin (A) Emulsion resin Ethylene-vinyl acetate emulsion Emulsion manufactured by Kuraray Co., Ltd .: Panflex OM-5500 10.0% by weight (B) Water-soluble resin acetylated starch Oji Corn Starch Co., Ltd .: Ace K-500 6.0% by weight (C) Water-soluble resin Partially saponified PVA Kuraray Co., Ltd .: Kuraray Poval PVA420 24.0% by weight ・ White pigment silica gel Mizusawa Chemical Co., Ltd .: Mizukasil P-78D 40.0% by weight ・Cationic dye fixing agent Polyamine-based dye fixing agent Sumitomo Chemical Co., Ltd .: Sumirezu Resin 784S 10.0% by weight ・ Light fastness improving agent Divalent or higher-valent water-soluble metal salt Tomita Pharmaceutical Co., Ltd .: Magnesium chloride S 10.0 weight%

<Example 5> In Example 1, the ink receiving layer on the back surface was provided with an ink receiving layer having the following composition after providing the ink receiving layer on the surface of the support. Similarly, an ink jet recording medium was produced. Water-soluble resin partially saponified PVA Kuraray Co., Ltd .: Kuraray Poval PVA420 40.0% by weight White pigment silica gel Mizusawa Chemical Co., Ltd .: Mizukasil P-78D 40.0% by weight Cationic dye fixing agent Polyamine dye fixing agent Sumitomo Chemical Industries, Ltd .: Sumirezu Resin 784S 10.0% by weight-Lightfastness improving agent Divalent or higher valent water-soluble metal salt Tomita Pharmaceutical: Magnesium chloride S 10.0% by weight

Comparative Example 1 Binder resin (A) Emulsion resin Ethylene-vinyl acetate emulsion Emulsion made by Kuraray: Panflex OM-5500 10.0% by weight (B) 0.0 % by weight without water-soluble resin ( C) Water-soluble resin partially saponified PVA Kuraray Co., Ltd .: Kuraray Poval PVA420 30.0% by weight ・ White pigment silica gel Mizusawa Chemical Co., Ltd .: Mizukasil P-78D 40.0% by weight ・ Cationic dye fixing agent Polyamine dye fixing agent Sumitomo Chemical Co., Ltd .: Sumirezu Resin 784S 10.0% by weight-Agent for improving light resistance Water-soluble metal salt having a valency of 2 or more Tomita Pharmaceutical Co., Ltd .: Magnesium chloride S 10.0% by weight

Comparative Example 2 Binder resin (A) 0.0 % by weight without emulsion resin (B) Water-soluble resin Oxidized starch manufactured by Oji Cornstarch: Ace A 10.0% by weight (C) Water-soluble resin Saponified PVA Kuraray Co., Ltd .: Kuraray Poval PVA420 30.0% by weight ・ White pigment silica gel Mizusawa Chemical Co., Ltd .: Mizukasil P-78D 40.0% by weight ・ Cationic dye fixing agent Polyamine dye fixing agent Sumitomo Chemical Co., Ltd .: Sumirezu Resin 784S 10.0% by weight-Lightfastness improving agent Divalent or higher valent water-soluble metal salt Manufactured by Tomita Pharmaceutical Co .: Magnesium chloride S 10.0% by weight

Comparative Example 3 Binder resin (A) Emulsion resin Ethylene-vinyl acetate emulsion Emulsion manufactured by Kuraray Co., Ltd .: Panflex OM-5500 10.0% by weight (B) Water-soluble resin Oxidized starch Oji Cornstarch Co., Ltd .: Ace A 30.0% by weight (C) 0.0 % by weight not containing water-soluble resin ・ White pigment silica gel 40.0% by weight Mizukasil P-78D manufactured by Mizusawa Chemical Co. ・ Cationic dye fixing agent Polyamine dye fixing agent Sumitomo Chemical Manufactured by Kogyo Co .: Sumireze Resin 784S 10.0% by weight-Agent for improving light resistance Water-soluble metal salt having a valency of 2 or more Manufactured by Tomita Pharmaceutical Company: 10.0% by weight of magnesium chloride S

The materials of the ink receiving layers in Examples 1 to 5 and Comparative Examples 1 to 3 have been described above, and the materials for the gloss adjusting layer applied on the ink receiving layers made of these materials are all common. The materials are as follows. [Material for Glossiness Adjusting Layer] Binder resin Fully saponified PVA Nippon Gohsei Chemical: Gohsenol N-300 10.0% by weight White pigment Colloidal silica Nissan Chemical Industries, Ltd .: Snowtex UP 45.0% by weight Nissan Chemical Industry Co., Ltd .: Snowtex XL 45.0% by weight

For the ink jet recording media of Examples 1 to 4 and Comparative Examples 1 to 3, commercially available ink jet printers (PM-750C, manufactured by Seiko Epson Corporation)
The following evaluation test and measurement of air permeability were carried out.

(1) One Side of Print Density Inkjet Recording Medium (Front Side in Example 5)
Prints a color patch on the GRETAG S spectrophotometer
Using PM50 (manufactured by Gretag Macbeth), the reflection density of each color of black, cyan, magenta, and yellow was measured, and the image print density characteristics were evaluated. Table 1
Shows only the measurement data on the front side). (2) One Side of Image Clearness Inkjet Recording Medium (Front Side in Example 5)
Prints a color patch on the GRETAG S spectrophotometer
Using PM50 (manufactured by Greta Macbeth), saturation of each color of cyan, magenta, and yellow C = (a ² + b ² )
^{One half} was measured and evaluated (evaluation results show that all samples had the same image quality on the front and back, and Table 1 shows only the measurement data on the surface). (3) Cockling Black solid printing with an optical density of 1.0 was performed on both surfaces of the inkjet recording medium, and the degree of cockling (wavy) on the printed surface was visually evaluated as follows. A: No cockling is observed. B: Cockling was slightly recognized, but practically no problem at all. C: Cockling is clearly observed.

(4) One Side of Offset Inkjet Recording Medium (Front Side in Example 5)
Is printed with a color patch, and immediately thereafter, the ink receiving layer of another ink jet recording medium is pressed from above,
The set-off of the undried part was visually evaluated as follows. A: No set-off is observed. B: Set-off is recognized to the extent that it cannot be determined without enlargement, but there is no practical problem. C: Set-off can be determined by appearance, and there is a practical problem.

(5) Image Strength One side of the inkjet recording medium (the front side in Example 5)
Then, black solid printing with an optical density of 1.0 was performed, and this was again passed through the printing conveyance path of the printer. The jaggedness caused by the lack of the recorded image by the transport roller on the already printed surface was visually evaluated as follows. A: No loss of the recorded image is observed. B: Although there is a slight dent, no deterioration in image quality is observed and there is no practical problem. C: A part of the recorded image is missing and there is a practical problem.

(6) Light fastness / light fastness 1 (residual density) For a print sample of a color patch similar to the above (4), a xenon weatherometer (manufactured by ATLAS: Ci-
5000), a black panel temperature of 63 ° C., a relative humidity of 50% and an ultraviolet irradiation intensity of 340 nm of 0.35 W / m ^2.
An exposure test of 30 kJ / m ² was performed under the following conditions. Next, a spectrophotometer (GRETAG, manufactured by Gretag Macbeth)
The reflection density of M (magenta) was measured using SPM50), and the light resistance corresponding to the residual density was evaluated as follows. A: The concentration after exposure exceeds 90% before exposure. B: The concentration after exposure was 80 to 90% of that before exposure. C: The concentration after exposure is less than 80% of that before exposure.

[0045]・ Light resistance 2 (light yellowing) Xenon weatherometer (manufactured by ATLAS: Ci-50
00), a black panel temperature of 63 ° C. and a relative humidity of 5
0%, UV irradiation intensity at 340 nm 0.35 W / m²Article
30kJ / m²Inkjet recording of exposure test
The test was performed on a recording medium (unrecorded product). Then the spectrophotometer
Total (GRETAG SPM5 by Gretag Macbeth)
Inkjet recording medium itself measured using 0)
L^*, A ^*, B^*Before and after exposure calculated from the values of
Is the color difference of ΔE, and from the value of ΔE, the degree of light yellowing is
Was evaluated. A: The value of ΔE is less than 5. B: The value of ΔE is 5 to 10. C: The value of ΔE exceeds 10.

Lightfastness 3 (residual density) facing south. A color patch print sample of Y (yellow), M (magenta), C (cyan), and Bk (black) was allowed to stand over a glass window for about one month. Thereafter, the average value of the residual concentration ratio was measured and evaluated as follows. A: The concentration after standing exceeds 90% before leaving. B: 80-90% of the density after standing. C: The concentration after standing was less than 80% of that before standing.

Lightfastness 4 South facing R (red), G (green), through glass window
The B (blue) color patch print sample was left for about one month. Next, the L measured using a spectrophotometer (GRETAG SPM50 manufactured by Gretag Macbeth) was measured.
The color difference before and after standing obtained from the values of ^* , a ^* , and b ^* was defined as ΔE, and the average value of ΔE for each of R, G, and B was evaluated as follows. A: The average value of ΔE is less than 5. B: The average value of ΔE is 5 to 10. C: The average value of ΔE exceeds 10.

(7) Room preservation A print sample (portrait image) of an ink jet recording medium is placed on an office wall about 2 m away from a north facing window.
Was stuck and left for 6 months, and then the indoor storage stability was visually evaluated as follows. A: No change in color compared to the initial stage. B: It turns out that the color changed compared with the initial stage.

(8) Preservation of Clear File An inkjet recording medium (unrecorded product) is stored in a clear file (CL-A420) manufactured by Mitsubishi Pencil Co. so as to protrude by about 2 cm and stored at 60 ° C. for 2 weeks. Thereafter, the degree of yellowing is determined by the color difference ΔE (CIE L ^* a ^*)
b ^* ) was evaluated as follows. A: ΔE is less than 2. B: ΔE is 2-5. C: ΔE exceeds 5.

(9) Pure glossy paper (manufactured by Seiko Epson: Super Fine glossy paper (thick mouth)) by visually observing the degree of bleeding of mixed colors and bleeding in a single color with an ink-absorbing inkjet printer.
(Photo-printed paper) and evaluated as follows. The difference between the SCID images is high-definition color digital standard image data, and is defined as ISO / JIS-SCID (JIS X
9201-1995) in comparison with the N1 portrait image or the N3 fruit basket image. A: Practically excellent without any problem (equivalent to or higher than pure glossy paper). B: Excellent without practical problems (slightly inferior to genuine glossy paper, but no difference in SCID image is recognized). C: Poor in practical use (there is also a difference in SCID images).

(10) Image Water Resistance Y (Yellow), M (Magenta), C (Cyan), R
(Red), G (green), B (blue), and Bk (black) are printed, one drop of water is attached to the printed portion, and the air-dried state is as follows. evaluated. A: Dye does not flow out. B: There is run-off of the dye, but it is legible. C: Not legible.

(11) Image moisture resistance Y (yellow), M (magenta), C (cyan), R
(Red), G (Green), B (Blue), Bk (Black) samples printed with color patches at 40 ° C.
The film was exposed to a high-humidity condition of 85% for three days and nights, and the moisture resistance of the image was evaluated as follows from the deepening of the color patch and the degree of blurring of the outline. A: Practically excellent without any problem (no darkening, no contour bleeding). B: Excellent without practical problems (slight bleeding). C: Practically inferior.

(12) Water-Resistance of the Ink-Receiving Layer 5 mL of water was dropped on the ink-receiving layer, and breakage or peeling of the ink-receiving layer caused by rubbing on the water was examined, and evaluated as follows. A: Excellent (no breakage or peeling of the ink receiving layer is observed). B: Excellent without practical problem (peeling of the ink receiving layer is slightly observed, but the image is retained). C: There is a problem in practical use (the ink receiving layer is broken and the root is peeled off).

(13) Water Resistance of Glossiness Adjusting Layer 5 mL of water is dropped on the glossiness adjusting layer, and breakage or peeling of the glossiness adjusting layer caused by rubbing thereon is examined, and evaluated as follows. . A: Excellent (no breakage or peeling of the glossiness adjusting layer is observed). B: Excellent without practical problems (slight peeling of the glossiness adjusting layer is observed). C: There is a problem in practical use (the glossiness adjusting layer is broken and the root is peeled off).

(14) Air Permeability The air permeability of an unrecorded ink jet recording medium is determined according to “J.
TAPPI paper pulp test method No. It was measured by the Oken type air permeability test method specified in "5."

The evaluation results and the measurement results of the above tests were
It is shown in Table 1.

[0057]

[Table 1]

According to Table 1, the evaluation results of the ink jet recording media of the examples all show a high level of A, and the air permeability is 100 or less, indicating high ink absorbency. Therefore, it was confirmed that cockling and set-off were prevented, the image strength was sufficient, and the image recording quality such as light fastness, image storability, and water fastness was excellent. On the other hand, the inkjet recording medium of the comparative example
In particular, cockling, set-off, image strength and ink absorptivity were inferior, and had practical problems. As a result, it was proved that the ink jet recording medium of the present invention was not only excellent in image recording quality but also extremely promising as an ink jet recording medium for double-sided recording.

[0059]

As described above, according to the present invention, the binder resin in the ink receiving layer is composed of an emulsion resin, at least one water-soluble resin selected from starch and cellulose derivatives, and a binder resin other than starch and cellulose derivatives. Since it contains three components of a water-soluble resin, it not only excels in image recording quality such as print density and image storability (light resistance, water resistance, moisture resistance, etc.), but also increases the thickness and reverses the image. Transfer is suppressed, and good ink absorbency and prevention of cockling are both achieved. Therefore,
It is very promising as an ink jet recording medium for double-sided recording, and has an effect that it can be used for full-color high-speed printing technology because of its excellent ink absorbency.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D21H 19/54 D21H 19/58 19/58 19/60 19/60 B41J 3/04 101Y (72) Inventor Nobuhiro Kubota 3-1 Yomiba-cho, Shizuoka City, Shizuoka Prefecture Inside the paper division of Hamakawa Paper Mill Co., Ltd. (72) Inventor Takeshi Yoshimoto 3-1 Yomiba-cho, Shizuoka City, Shizuoka Prefecture Inside the Paper Division of Hamakawa Paper Mill Co., Ltd. 72) Inventor Shinichiro Kobayashi 3-1 Yomoe-cho, Shizuoka-shi, Shizuoka Prefecture Inside the paper division of Hamakawa Paper Mill Co., Ltd. (72) Inventor Kiyoshi Iwamoto 3-1 Yomoe-cho, Shizuoka-shi, Shizuoka Prefecture Tomoe Paper Mill Co., Ltd. Inside the Paper Division (72) Inventor Hiroyuki Onishi 3-3-5 Yamato, Suwa City, Nagano Prefecture Inside Seiko Epson Corporation (72) Inventor Jun Sugiyama 3-3-3 Yamato, Suwa City, Nagano Prefecture No. 5 F-term in Seiko Epson Corporation (Reference) 2C056 FC06 2H086 BA16 BA24 BA33 BA34 BA35 BA41 4L055 AG18 AG46 AG48 AG59 AG64 AG89 AG97 AH02 AH37 AJ04 EA11 EA12 EA32 FA15 FA18 FA30 GA09

Claims (6)

[Claims] 1. An ink jet recording medium in which an ink receiving layer containing a pigment and a binder resin is coated on at least one surface of a support, wherein the binder resin comprises an emulsion resin (A), starch and cellulose. An ink jet recording medium comprising at least one water-soluble resin (B) selected from derivatives and a water-soluble resin (C) other than starch and a cellulose derivative. 2. The ink jet recording medium according to claim 1, wherein the ink receiving layer is coated on both surfaces of the support. 3. 100 parts by weight of the emulsion resin
The water-soluble resin (B) is blended in an amount of 20 to 125 parts by weight and the water-soluble resin (C) is blended in an amount of 20 to 600 parts by weight with respect to (A). 3. The ink jet recording medium according to 2. 4. The ink jet recording medium according to claim 1, wherein the air permeability is 10 to 1000 seconds. 5. The ink jet recording medium according to claim 1, further comprising a glossiness adjusting layer on the outermost surface of the ink receiving layer. 6. The ink jet recording medium according to claim 5, wherein the glossiness adjusting layer has a mirror glossiness of 60 degrees of 10 or more.